Understanding processes that control the retention and flow of water in peat soils is critical to effective management of such soils from both agricultural and ecological perspectives. Water retention of peats collected in rubber-cultivated, oil palm-cultivated, and abandoned peatlands were characterized using the van Genuchten equation. The present study showed that more decomposed peats in the rubber cultivated peatland lose their water relatively slowly at small negative pressure heads, while less decomposed peats in the oil palm-cultivated and abandoned peatlands lose their water more quickly. This reflects difference of pore-size distribution among different land uses of peatlands. This phenomenon is also applied to acrotelm and intermediate peat layers that are different decomposed states. Total volume of water retained by unsaturated layers in the rubber-cultivated peatland was lower than that in the oil palm-cultivated and abandoned peatlands. Otherwise, the residual water content was higher in the rubber-cultivated peatland compared to the oil palm-cultivated and abandoned peatlands. This implies that a part of the maximum volume of water being removed decreases as a result of agricultural activities in peatlands. This evidence shows that the moisture state of peat soil was greatly influenced by the degree of peat decomposition and water table fluctuation. Based on parameters α and n, unsaturated peat layers in the oil palm-cultivated peatland will be loss water higher and more rapidly than in the rubber cultivated peatland during the early period of decline in water table. This result can be explained that water retention curve will be flat in case of compression as a part of the macro pores decreases and vice versa a part of micropores increases.